Prior art of possible relevance includes the following U.S. Pat. Nos.: 1,527,807 issued Feb. 24, 1925 to Loguin; 2,475,247 and 2,494,100 respectively issued on July 5, 1949 and Jan. 10, 1950 to Mikulasek; 3,989,422 issued Nov. 2, 1976 to Guttinger; 4,141,677 and 4,157,234 respectively issued on Feb. 27, 1979 and June 5, 1979 to Weaver et al; 4,365,941 issued Dec. 28, 1982 to Tojo et al; 4,457,674 issued July 3, 1984 to Kawano; 4,457,676 issued July 3, 1984 to Hiraga; 4,472,120 issued Sept. 18, 1984 to McCullough; and 4,477,239 issued Oct. 16, 1984 to Yoshii.
Positive displacement apparatus of the scroll type have been proposed in a variety of configurations over several decades. Generally speaking, they may be divided into two different categories. In one classification are those wherein the scrolls are non-rotating but wherein one scroll orbits with respect to the other. In the second classification, there is relative orbiting between the scrolls and both rotate relatively synchronously as well.
In either type, but particularly the type of the latter category, where the apparatus is used as a pump such as a compressor, to maximize efficiency it is desirable to take maximum advantage of ram air pressure available at the inlet which typically is defined by the radially outer ends of the spiral-like vane employed in such apparatus.
It is also desirable to minimize the draft force being applied to the outer wraps of the vanes during operation which drag of course requires a higher energy input to maintain a given speed than would be necessary if the drag could be reduced.
The present invention is directed to overcoming one or more of the above problems.